Display screen having regions of differing pixel density

ABSTRACT

A display device including: a display screen having first region and second region, the first region having a first pixel density and the second region having a second pixel density, the second pixel density being higher than the first pixel density, an input for receiving image data, a power source; and wherein the display screen is operable in a full screen mode in which an image is displayed in both the first region and the second region and a reduced screen mode in which power to the first region is turned off and the image is displayed in the second region.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.12/907,829, filed Oct. 19, 2010, which is fully incorporated byreference herein.

TECHNICAL FIELD

The present embodiments relate to display screens.

BACKGROUND

When operating any type of electronic device having a display screen(which may be referred to for convenience as a “display device”), it isdesirable to reduce the amount of power that is consumed. For desktopcomputers, for example, conserving power reduces operating costs, whilefor laptop computers and other portable electronic devices, conservingpower may extend battery life.

As laptop display screens, for example, continue to increase in size,such as 17 inch (43 cm) and larger screens, the impact on the batterylife becomes more significant. Liquid Crystal Display (LCD) screens mayinclude a backlight panel that is on when the display screen is on. Onetechnique for conserving power is to reduce the brightness of thedisplay screen or backlight panel. This power conservation method hasthe disadvantage that the dimmer display may degrade the visualexperience of viewing the information for the user.

Since display screens may consume a significant portion of the powerconsumed by electronic display devices, other methods for reducing theamount of power consumed by display screens are desirable.

DRAWINGS

The following figures set forth embodiments in which like referencenumerals denote like parts. Embodiments are illustrated by way ofexample and not by way of limitation in the accompanying figures.

FIG. 1 is a schematic front view of a display screen of a display deviceaccording to an embodiment;

FIG. 2 is a block diagram of a display device according to anembodiment;

FIG. 3 is a flowchart depicting a method of conserving power whenoperating a display device according to an embodiment;

FIG. 4A is a front view of display screen operating in a full screenmode;

FIG. 4B is a front view of a display screen operating in a reducedscreen mode;

FIG. 5 is an enlarged view of portions of FIG. 4B;

FIG. 6 is an isometric view of an example of a display device accordingto an embodiment; and

FIGS. 7A-7C are schematic front views of alternate embodiments of thedisplay screen of FIG. 1.

DETAILED DESCRIPTION

There is provided herein a method for conserving illumination power of adisplay screen including: consuming power by displaying a largerilluminated image on the display screen and conserving power by reducingthe size and increasing the resolution of the illuminated image on thedisplay screen.

There is provided herein a display device including: a display screenhaving first region and second region, the first region having a firstpixel density and the second region having a second pixel density, thesecond pixel density being higher than the first pixel density; an inputfor receiving image data; and a power source; wherein the display screenis operable in a full screen mode in which an image is displayed in boththe first region and the second region and a reduced screen mode inwhich power to the first region is turned off and the image is displayedin the second region.

There is further provided herein a method of operating a display screen,the display screen in communication with a processor and a source ofpower, the method comprising: illuminating a first region and a secondregion of the display screen to display a first image, the second regionhaving a higher pixel density than the first region; receiving, at theprocessor, a power conservation signal; and turning off power to thefirst region of the display screen in response to the power conservationsignal; wherein illumination of the second region is continuous.

Referring to FIG. 1, a display device 10 includes a display screen 14,which is mounted in a housing 16, and an input 18. Input 18 may be aport for coupling to a cable or may be a wireless receiver. In oneembodiment the input 18 receives data (which may include photographs,video, graphical elements or any other data that may be displayed in anyfashion on the display device 10) and power. In another embodiment,separate data and power inputs are provided. The display screen 14 maybe a liquid crystal display (LCD) screen including a thin filmtransistor LCD screen with a multi-segment electro luminescence (EL)backlighting panel. Alternatively, the display screen 14 may be a plasmadisplay screen, light emitting diode (LED) or another type ofilluminated display screen. The display screen 10 may be a stand-alonecomponent, or may be a part of a larger system or collection ofcomponents. For example, the display screen may be a part of atelevision, laptop or desktop computer system, smart phone, touch screeninput/output interface, gaming system, and the like.

The display screen 14 includes a first region 20 and a second region 22.In an LCD screen embodiment, the first region 20 includes acorresponding first EL portion (not shown) and the second region 22includes a corresponding second EL portion (not shown) that isindependently operable from the first EL portion. The second region 22may be generally rectangular-shaped and may be located centrally withinin the display screen 14. In the embodiment depicted in FIG. 1, the areaof the second region 22 is approximately one-sixteenth the area of thefirst region 20. The shape of second region 22, the location of thesecond region 22 in relation to the display screen 14 as a whole, andthe relative sizes of the second region 22 with respect to the firstregion 20 are merely illustrative, and the concepts are not restrictedto the particular embodiment depicted in FIG. 1. Further, the conceptdescribed herein may be applicable to a display screen that has two ormore regions that are like the second region 22. As shown, a first pixeldensity of the first region 20 is lower than a second pixel density ofthe second region 22. The respective pixel densities are often measuredin pixels per unit length; such as pixels per inch (ppi) and aretypically determined at the time of display screen manufacture. Forexample, the first region 20 may be the size of a laptop display with a14 inch (36 cm) 1024×768 XGA (Extended Graphics Array) display having apixel density of 90 ppi and the second region 22 may be approximatelythe size of a handheld device screen, such as a PDA (Personal DigitalAssistant) or smart phone with a 3.25 inch (8.25 cm) 480×360 VGA (VideoGraphics Array) display having a pixel density that is twice the pixeldensity of the first region 20.

The display screen 14 is operable in a full screen mode, in whichilluminated images fill both the first region 20 and the second region22, and a reduced screen mode, in which illuminated images fill thesecond region 22 only. Reduced screen mode also includes situations inwhich illuminated images fill part of the second region 22, andsituations in which there may be some slight image spill-over into thefirst region 20. When operating in the full screen mode, the resolutionof the display screen is less than or equal to a full screen maximumresolution, which is determined based on the first pixel density of thefirst region 20. In the full screen mode, images may appear seamless tothe user so that the second region 22 is generally undetectable. Whenoperating in the reduced screen mode, the resolution of the secondregion 22 is increased. Based on the respective pixel densities, thereduced screen maximum resolution is higher than the full screen maximumresolution. The reduced screen mode may conserve power by turning offpower to the first region 20 and illuminating the second region 22 onlyor illuminating part of the second region 22 or illuminating the secondregion 22 principally. “Turning off” power to the first region 20 mayinclude completely shutting down all power to the first region 20 andmay also include putting the first region 20 into a low-power or standbymode, or causing the first region to turn black or monochromatic or thelike.

In one embodiment, the second region 22 has a pixel density 2× the pixeldensity of the first region 20. In another embodiment, the second region22 has a pixel density that is more than 2× the pixel density of thefirst region 20.

The reduced screen mode is used to display high resolution images in arelatively small area. In one implementation, an image in regularresolution on the full screen can be comparable to ordinary display ofimages on the display screen, while displaying a high resolution imagein the second region 22 can be comparable to displaying an image on asmaller portable, typically handheld, electronic device. In this way,displaying a high resolution image in the second region 22 can simulatethe user experience when operating a handheld device, such as a smartphone or a PDA, for example. Because many users are accustomed toviewing handheld device screens, operating a larger screen displaydevice 10 in a reduced screen mode is an easy transition. Some imagesmay be more suited to display in a reduced screen mode than others. Suchimages may include video, electronic book images and e-mail messageimages, for example.

In one example, the first region 20 has a ppi corresponding to a 14 inchVGA screen. The first region 20 includes substantially 0.74 mega pixels,which is the standard 0.786 megapixel XGA screen less the second region22. The second region 22 has a ppi substantially corresponding to a 3.25inch XGA screen and includes 0.17 mega pixels. Thus, display screen 14includes 0.91 megapixels, the sum of the pixels of regions 20 and 22.

Referring to FIG. 2, the display device 10 is shown in communicationwith a computer 30. The computer 30 includes a processor 32, whichcontrols overall operation thereof. A video card 36 communicates withthe processor 32 and generates graphic elements based on image datareceived from the processor 32. This process is referred to as renderingand generally includes mapping out the graphic elements in preparationfor display. The processor 32 and video card 36 are generally circuitboards that are coupled to one another. The processor 32 and video card36 may alternatively be provided in a single circuit board.

The processor 32 communicates with a Random Access Memory (RAM) (notshown) and a flash memory 34. An operating system 38, display driver 40and software are typically stored in flash memory and are executable bythe processor 32. The display driver 40 functions to translate softwarecommands that are stored in memory 34 into commands for controlling thedisplay device 10.

In the 14 inch VGA screen and 3.25 inch XGA screen example, while thedisplay driver 40 is adapted to drive the 0.91 megapixel display screen14, the pixel memory in display driver 40 need only be capable ofrendering a 0.786 or smaller megapixel image. In the full screen mode,four adjacent pixels in the second region 22 can be redundantly drivenby rendered image data corresponding to one pixel in first region 20,thus providing an XGA image having the same resolution in first andsecond regions 20, 22. In the reduced screen mode, the pixel memory indisplay driver 40 need only be capable of rendering 0.17 megapixel XGAimage in second region 22, eliminating the redundant driving of pixelsfrom the full screen mode and independently driving each pixel in secondregion 22.

The computer 30 includes computer executable programmed instructions fordirecting the computer 30 (or a tangible component of the computer 30 ora tangible device controlled by computer 30) to implement variousapplications. Some examples of applications that may be stored on andexecuted by the computer include: electronic messaging, games, calendar,address book and music player applications. It will be appreciated by aperson skilled in the art that the flash memory may alternatively be apersistent storage, a Read-Only Memory (ROM) or other non-volatilestorage. Some software components may alternatively be stored in RAM.

The processor 32 receives input from an input device 24, such as akeyboard, multifunction buttons, a touch pad, a touch screen, a mouse ora trackball, for example. The input device 24 may include a singledevice or more than one device. The computer 30 outputs image data tothe display device 10 for display on the display screen 14. Theprocessor 32 may further output to other devices (not shown) includingan auxiliary display screen and a speaker, for example.

The display screen 14 switches between the full screen mode and thereduced screen mode when a signal (which will be referred to forconvenience as a “power conservation signal”) is received by theprocessor 32. Power conservation signals may be generated when reducedscreen-suitable images are to be displayed and the power to the firstregion 20 is turned off. For example, a power conservation signal may begenerated when: an electronic book application is launched, an emailmessage is opened or a video application is launched, for example.Launching of applications and opening of email messages is well known inthe art. These operations may be performed by a user operating the inputdevice 24. For example, an application may be launched by user selectionof an application icon on a desktop or navigation through menus.Similarly, an email message may be opened when a user double clicks on amessage using a mouse or highlights the message and selects “open” froma menu, for example.

Referring to FIG. 3, a method for conserving power when operating thedisplay device 10 is generally shown. The method is stored as acomputer-readable file that includes instructions corresponding to themethod and is executable by the processor 32. The method generallyapplies when the display screen 14 is in communication with theprocessor 32 and a power source. The method includes; at step 44,illuminating a first region 20 and a second region 22 of the displayscreen 14 to display a first image, the second region having a higherpixel density than the first region; at step 46, receiving, at theprocessor 32, a power conservation signal; at step 48, turning off powerto the first region 20 of the display screen 14, the power being turnedoff in response to the power conservation signal and illumination of thesecond region is continuous to display a second image. In general,illumination of the second region is “continuous” in the sense that thesecond region does not get turned off while the first region does getturned off. Although it may be advantageous for illumination of thesecond region to show no change whatsoever, the illumination of thesecond region may be deemed “continuous” even if there are sometransient or transitional changes in illumination of the second regionwhen the first region is turned off.

Referring to FIGS. 4A and 4B, an example of a software, such as an emailapplication, being displayed on the display screen 14 is provided. InFIG. 4A, the display screen 14 is operating in a full screen mode and inFIG. 4B, the display screen 14 is operating in a reduced screen mode.

As shown in FIG. 4A, a window of an email application is displayed.Opening an email message 54 sends a power conservation signal to theprocessor 32. In response to the power conservation signal, power to thefirst region 20 is turned off and a message window corresponding toemail message 54 is displayed in the second region 22, as shown in FIG.4B and FIG. 5.

In another example, opening a movie could result in a similar sequenceof display size reduction, with the movie opened in a full screen userinterface displayed corresponding to FIG. 4A and viewed within in thereduced display area of FIG. 4B and FIG. 5. Watching a two hour movie ona laptop with a 14 inch XGA display can place a significant demand onthe battery, however, watching the same movie within a 3.25 inch VGAdisplay region provides an illumination area that is 5% of the 14 inchXGA screen and can conserve up to 95% of the power expended for screenillumination, thereby substantially extending the battery life of thedevice while providing an acceptable video viewing experience.

Referring to FIG. 6, an example of a display device 10 is shown. In thisexample, the display device 10 is a monitor of a laptop computer 100.The monitor includes a Liquid Crystal Display (LCD) display screen 114,a keyboard 116 and a touch pad 118. The laptop computer 100 may beprovided in communication with a network, such as the Internet, a LocalArea Network (LAN) or a Wide Area Network (WAN), for example. The laptopcomputer 100 may be in wireless communication with the network or maycommunicate with the network via a wired connection. Directcommunication with other computers may also occur directly viaBluetooth™ technology, for example. Alternatively, the laptop computer100 may not communicate with the network and may operate independently.

Referring to FIGS. 7A-7C, the second region 22 is not limited to beingprovided centrally relative to the first region 20. The second region 22may be provided at a left side, a bottom side or a corner, for example,as shown.

It will be appreciated by a person skilled in the art that the displaydevice 10 may be any device including a display screen of a typicaldisplay device including: a monitor for a desktop computer or anauxiliary monitor of a desktop or laptop or pad-type computer, atelevision, portable DVD player, a PDA or even a portable communicationdevice such as a cell phone or pager where the image size is reducedwhile its resolution is increased to preserve power while facilitatingan enhanced viewing experience.

In one embodiment, the brightness of the second region 22 may be dimmedto provide further power conservation for LCD screen applications.

In another embodiment, the first region 20 and the second region 22 areoperated together, however, the second region 22 is operated at aresolution that is greater than the full screen maximum resolution. Inone example, high resolution images may be displayed in the secondregion 22 while text is displayed in the first region 20.

The embodiments disclosed herein may reduce the amount of power consumedby a display screen when reduced screen-suitable images are displayed.By turning a portion of the screen illumination off during display ofreduced screen-suitable images, less power may be consumed. Theseembodiments need not be exclusive of other power-saving techniques.

Although the concepts have been described herein as providing apotential benefit of power-saving, power-saving is not essential to theconcepts. There conceivably may be circumstances in which the conceptsdescribed herein may provide no power-saving, and generation of thepower conservation signal does not result in an actual conservation ofpower. Further, other potential benefits may be realized, including theability to focus in on selected portions of an image, making detailsmore visible at a high resolution, or making ready adaptation ofsmall-screen-high-resolution software applications on a larger displayscreen.

Specific embodiments have been shown and described herein. However,modifications and variations may occur to those skilled in the art. Allsuch modifications and variations are believed to be within the scopeand sphere of the present embodiments.

The invention claimed is:
 1. A display device comprising: a displayscreen comprising a first region and a second region, the first regioncomprising a first pixel density to display images having a firstresolution, the first resolution being up to the first pixel density,and the second region comprising a second pixel density to displayimages having a second resolution, the second resolution being up to thesecond pixel density, the second pixel density being higher than thefirst pixel density, the display screen operable in a full screen modein which an image is displayed in both the first region and the secondregion and a reduced screen mode in which power to the first region isturned off and the image is displayed in the second region, in the fullscreen mode, some pixels of the second region are redundantly driven byrendered image data of the first resolution so that the first resolutionand the second resolution of the image are the same; an input forreceiving image data; a power source; and a processor in communicationwith the display screen, the input and the power source; wherein thesecond resolution of the image displayed in the second region is greaterthan the first resolution.
 2. The display device of claim 1, wherein thedisplay screen is a liquid crystal display (LCD) screen with a variablearea electro luminescence (EL) backlight or a plasma display screen. 3.The display device of claim 1, wherein the second pixel density is atleast two times higher than the first pixel density.
 4. The displaydevice of claim 1, wherein the first region is the size of a displayscreen of a laptop computer and the second region is the size of ahandheld device screen.
 5. The display device of claim 1, wherein thesecond region is approximately five percent the size of the firstregion.
 6. The display device of claim 1, wherein the number of pixelsper inch of the second region corresponds to a 3.25 inch ExtendedGraphics Array screen.
 7. The display device of claim 1, wherein in thefull screen mode, four adjacent pixels of the second region are drivenby rendered image data corresponding to one pixel in the first region.8. The display device of claim 1, wherein the second region is centrallylocated relative to the first region.
 9. A method of operating a displayscreen, the display screen in communication with a processor and asource of power, comprising: illuminating a first region and a secondregion of the display screen in a full screen mode to display a firstimage, the second region having a higher pixel density than the firstregion and some pixels of the second region being redundantly driven todisplay the first image with a same resolution in the first region andthe second region, the same resolution being less than or equal to apixel density of the first region.
 10. The method of claim 9, wherein,in the full screen mode, four adjacent pixels of the second region aredriven by rendered image data corresponding to one pixel in the firstregion.
 11. The method of claim 9, comprising turning off power to thefirst region in response to a power conservation signal and displayingthe first image in the second region having a resolution that is greaterthan the same resolution.
 12. The method of claim 11, wherein turningoff power to the first region comprises one of: shutting down all powerto the first region, operating the first region into a low-power orstandby mode and operating the first region in a monochromatic mode. 13.The method of claim 11, comprising dimming the second region.
 14. Themethod of claim 9, wherein the first image has a first resolution and asecond image displayed in the second region has a higher resolution thanthe first resolution.